Simultaneous determination of five bioactive secolignans in rat plasma by LC–MS/MS for pharmacokinetic studies following oral administration of Peperomia dindygulensis Miq. extract

Three new secolignans from Peperomia blanda (Jacq.) Kunth

Three new secolignans were found in the detailed chemical study of Peperomia blanda (Jacq.) Kunth collected from China. Detailed NMR data analysis, especially ¹H NMR, ¹³C NMR and 2 D NMR, elucidates the structures of the three new secolignans.

Simultaneous Determination of 12 Marker Components in Yeonkyopaedok-san Using HPLC–PDA and LC–MS/MS

Yeonkyopaedok-san is a traditional Korean medicine used in the early treatment of boils. In the present study, its 12 marker components for quality control were determined using high-performance liquid chromatography (HPLC) with photodiode array detection and ultra-performance liquid chromatography–mass spectrometry with tandem mass spectrometry (UPLC–MS/MS). The investigated 12 marker components of Yeonkyopaedok-san were as follows: 3-caffeoylquinic acid, cimifugin 7-glucoside, liquiritin apioside, ferulic acid, narirutin, 5-O-methylvisammioside, naringin, neohesperidin, oxypeucedanin hydrate, arctigenin, glycyrrhizic acid, and 6-gingerol. The analytical column used for the separation of the 12 marker analytes in Yeonkyopaedok-san was a Waters SunFire C18 column (4.6 mm × 250 mm, 5 μm). The two mobile phases used were 0.1% (v/v) aqueous formic acid and 0.1% (v/v) formic acid in acetonitrile. In the UPLC–MS/MS analysis, all components were separated using a Waters ACQUITY UPLC BEH C18 column (2.1 mm × 100 mm, 1.7 μm). The two mobile phases used were 0.1% (v/v) aqueous formic acid and acetonitrile. The coefficient of determination of the calibration curves in both analysis systems showed good linearity (>0.99). The amounts of the 12 marker components in Yeonkyopaedok-san determined using HPLC–photodiode array detection and UPLC–MS/MS analyses were found to be 0.14–9.00 mg/g and 2.35–853.11 μg/g, respectively.

Peperomin E (PepE) protects against high fat diet-induced atherosclerosis in Apolipoprotein E deficient (ApoE-/-) mice through reducing inflammation via the suppression of NLRP3 signaling pathway

Peperomin E (PepE) is a type of secolignan, a major component of the plant Peperomia dindygulensis. It has been shown to exert anti-inflammatory effects; however, the effects of PepE on human atherosclerosis remain unexplored. In the study, we investigated the role of PepE in high fat diet (HFD) induced atherosclerosis using apolipoprotein E defcient (ApoE^-/-) mice. Elevated serum homocyteine, cholesterol, and triglyceride levels, accelerated progression of atherosclerosis and exacerbated macrophage infiltration into atherosclerotic lesions were observed in HFD-fed ApoE^-/- mice, which were attenuated by PepE treatment. ApoE^-/- mice fed with HFD exhibited significantly high levels of inflammation-associated regulators in artery tissues, accompanied with an increased expression of p-inhibitor of κBα (IκBα) and p-nuclear factor-kappa B (NF-κB), and the process was blocked by PepE administration. Further, we found NOD-like receptor pyrin 3 (NLRP3) inflammasome activation in artery tissues of HFD-fed ApoE^-/- mice. In vitro, silencing NLRP3 using small interfering RNA efficiently inhibited oxidized-low-density lipoprotein (oxLDL)-induced ASC and Caspase-1 expressions, interleukin (IL)-1β and IL-18 production in human aortic endothelial cells (HAECs). Further experiments indicated that NLRP3-ASC pathway was activated by reactive oxygen species (ROS), since ROS scavenger of N-acetyl-cysteine (NAC) prevented, which was further reduced by PepE addition. However, the anti-inflammatory effects of PepE on oxLDL-incubated HAECs were abolished by over-expression NLRP3. Together, our study revealed that PepE inhibited atherosclerosis development in HFD-fed ApoE^-/- mice by suppressing NLRP3 inflammatory signaling pathway, and suggested that PepE might be a potential therapeutic strategy in the prevention of atherosclerosis.

Determination of quantitative retention-activity relationships between pharmacokinetic parameters and biological effectiveness fingerprints of Salvia miltiorrhiza constituents using biopartitioning and microemulsion high-performance liquid chromatography

In this study, we analyzed danshen (Salvia miltiorrhiza) constituents using biopartitioning and microemulsion high-performance liquid chromatography (MELC). The quantitative retention-activity relationships (QRARs) of the constituents were established to model their pharmacokinetic (PK) parameters and chromatographic retention data, and generate their biological effectiveness fingerprints. A high-performance liquid chromatography (HPLC) method was established to determine the abundance of the extracted danshen constituents, such as sodium danshensu, rosmarinic acid, salvianolic acid B, protocatechuic aldehyde, cryptotanshinone, and tanshinone IIA. And another HPLC protocol was established to determine the abundance of those constituents in rat plasma samples. An experimental model was built in Sprague Dawley (SD) rats, and calculated the corresponding PK parameterst with 3P97 software package. Thirty-five model drugs were selected to test the PK parameter prediction capacities of the various MELC systems and to optimize the chromatographic protocols. QRARs and generated PK fingerprints were established. The test included water/oil-soluble danshen constituents and the prediction capacity of the regression model was validated. The results showed that the model had good predictability.